1. Field of the Invention
The subject invention generally pertains to refrigerant systems and more specifically to refrigerant systems that provide a reheat function in a cooling mode.
2. Description of Related Art
Refrigerant systems operating in a normal cooling mode typically have a refrigerant evaporator that cools a stream of air that is delivered to a room or some other comfort zone. Once the room's temperature (i.e., dry bulb temperature) reaches its target temperature, the refrigerant system may stop running. At times, however, this may leave the room uncomfortably humid. Thus, in some cases, the system may continue operating to reduce the humidity even after the sensible cooling demand of the room has been met.
To avoid over cooling the room in such cases, a heater downstream of the evaporator can be added to reheat the air after the evaporator cools and removes moisture from the air. Operating a refrigerant system in such a manner can be referred to as operating in a reheat cooling mode. In a reheat cooling mode, a refrigerant system can deliver relatively dry air to a room at a temperature close to its target temperature.
Often the heater is an electric coil, which effectively reheats the air, but wastes electrical energy. As an alternative to electric heat, a refrigerant condenser conveying hot refrigerant can possibly reheat the air. However, such an approach may create problems when the refrigerant system operates in modes other than the reheat cooling mode.
For example, when a refrigerant system with a reheat refrigerant condenser operates in a normal cooling mode without reheat, the inactive reheat condenser may flood with liquid refrigerant. The flooding may starve the rest of the system of its proper charge of refrigerant, thus reducing the system's overall efficiency in the normal cooling mode. Likewise, an inactive reheat condenser may flood and starve the rest of a refrigerant system when the system is operating in a heating mode to heat the comfort zone.